KR100266972B1 - Process for preparing reformed polyamide 6 fiber - Google Patents

Abstract

The present invention relates to a method for producing modified polyamide 6 fibers suitable for high-speed spinning, and more particularly, to producing polyamide 6 fibers by polymerizing caprolactam, using water as an initiator and organic dicar as chain regulator. In the process for producing modified polyamide 6 fibers suitable for high-speed spinning in which the acid is used to have an excess of carboxyl terminal relative to the amine terminal to improve melt stability and to improve the spinning by adding a magnesium compound before or after polymerization. It is about.

Description

Method of Making Modified Polyamide 6 Fibers

The present invention relates to a method for producing polyamide 6 fibers suitable for high-speed spinning, and more particularly, to producing polyamide 6 fibers by polymerizing caprolactam, using water as an initiator and organic dicarboxyl as a chain regulator. By using acid, it has excess carboxyl terminal compared with amine terminal to improve melt stability and add magnesium compound before or after polymerization to improve high-speed spinning which improves problems such as uneven physical properties and trimming of yarns generated during high-speed spinning. A process for the production of suitable modified polyamide 6 fibers.

Polyamide 6 is a linear polymer made of ε-carpolactam, and has excellent strength, elasticity, and abrasion resistance, low specific gravity, low hygroscopicity, low dryness, and excellent dyeing and chemical resistance. Due to such characteristics, polyamide 6 is widely used in medical fibers as well as industrial fibers and plastic molded articles.

Generally, polyamide 6 is prepared by ring-opening polymerization of ε-caprolactam or polycondensation of ω-aminocapronic acid. Polycaprolactam for fibers is prepared by limiting the molecular weight of the polyamide to a desired value and polymerizing the caprolactam in the presence of a chain regulator to ensure that the polyamide melt has a stable viscosity in the process.

In the production of polyamide 6 for fibers in the prior art, acetic acid was generally used as a terminal blocker of the polymer chain. Acetic acid stabilizes physical properties by spinning the amine terminal of the polymer to optimize molecular weight. However, this method using acetic acid as a terminal blocker is suitable for general spinning with a spinning speed of 4,000 m / min or less, but at higher spinning speeds, the actual equilibrium is not reached. There is a problem that the difference in physical properties and trimming of the liver, deterioration in elongation.

Therefore, the modification of the polymer is urgently required to improve the radioactivity. For such modification, a method of finely modifying the crystal structure of the polymer by combining or mixing mono or dicarboxylic acid, mono or diamine having good reactivity with caprolactam. Is proposed.

Conventionally, there exists a method of adding organic mono or dicarboxylic acid, organic mono, or diamine to a nylon polycondensation process as a method of making a fine deformation | transformation of such a crystal structure. For example, Japanese Patent Application Laid-Open No. 52-124927 discloses a method for producing polyamide fibers characterized by melt spinning a mixed composition consisting essentially of fiber-forming aliphatic polyamides, polyvalent amines, and magnesium compounds.

However, this method has excellent viscosity stabilization effect in general spinning, but it does not reach a substantial equilibrium state by high speed spinning in high speed spinning, which in turn promotes decomposition of polymers, resulting in differences in physical properties, trimming and elongation between radiators. There is an unsuitable problem in high speed spinning, such as causing a decrease.

U.S. Patent No. 2,174,527 discloses a method for stabilizing a polymer by blocking the amine end with an excess of dicarboxylic acid in the diacid-diamine polyamide, and U.S. Patent No. 2,241,321 provides sebacic acid in the presence of diamine. A method of polymerization using a chain extender is shown.

In addition, US Patent No. 3,386,967 has a high molecular weight of 25,000 to 40,000 number average molecular weight through a multi-step process using 0.1 to 0.7 mol% dicarboxylic acid, that is, adipic acid, sebacic acid, dodecanediol acid and terephthalic acid, etc. A method of preparing a polymer is disclosed, and US Pat. No. 3,839,530 discloses a method of using a dicarboxylic acid ester as a chain regulator. However, the ester compound is relatively volatile and thus difficult to maintain.

U.S. Patent No. 5,149,758 discloses a polyamide having high strength by using 0.1 to 0.6% by weight of terephthalic acid or isophthalic acid as the chain control agent with a total terminal content of 115 to 150 meq / kg and an amine terminal content of 25 meq / kg or more. A method of making a polymer is shown.

The conventional method described above has the advantage of stabilizing the polymer and obtaining a high strength polyamide by using dicarboxylic acid as a chain regulator of the polymer, but when melt spinning the polyamide for a long time at a high speed in this way, Volatile substances such as monomers and oligomers adhere to the spinneret surface and are oxidized in hot air and accumulated as carbides. Carbide accumulated on the spinneret surface not only causes bending of the molten polyamide during spinning, but also leads to trimming immediately when the bending of polyamide occurs, which causes a decrease in productivity and property irregularities. Becomes

Therefore, if the emission state is bad when spinning from the nozzle of the polymer for the production of a normal product, contamination around the nozzle discharge hole, bending of the emitting polymer is observed, the spinning is suspended and the spinning machine is stopped. After this, the release agent must be applied. This operation is called "nozzle wiping", and the period from the start of spinning to the nozzle correction is called "wiping cycle". The interruption of spinning operation due to the nozzle wiping eventually causes the polymer to stay in the spinning machine for a long time, causing problems such as deterioration of the polymer, generation of waste due to reactivation, and the cost required for wiping. There is a need for a method of improving productivity by extending the wiping cycle as far as possible in the manufacture of amide 6 fibers.

Accordingly, an object of the present invention is to provide a method for producing modified polyamide 6 fibers suitable for high-speed spinning by simultaneously improving the melt stability and spinning properties of the polymer in preparing the polyamide 6 fibers.

That is, the present invention, in the preparation of high-speed spinning modified polyamide 6 fibers, water is added as an initiator 0.2 to 5% by weight relative to caprolactam, 0.1 to 1.0% by weight of dicarboxylic acid as a chain regulator, and It is to provide a method for producing a modified polyamide 6 fiber characterized in that the caprolactam is polymerized by adding a magnesium compound at 10 to 100ppm based on the magnesium element.

The present invention is to prepare a polyamide 6 fiber by melt reaction at 240 ℃ to 300 ℃ using water as an initiator, dicarboxylic acid as a chain regulator and a mixture of magnesium compounds to improve the radioactivity at 240 ℃ to 300 ℃ It is to provide a method for producing a modified polyamide 6 fiber, characterized in that.

One aspect of the present invention is the use of dicarboxylic acids as polymer chain modifiers in the preparation of modified polyamide 6 fibers to have excess carboxyl ends relative to the amine ends to inhibit thermal degradation from the amine ends, thereby reducing the melt stability of the polymer. It is characterized in that to be suitable for high-speed spinning by improving the. That is, the amine terminal content of the extracted chip should be 30 to 60 meq / kg, and the total terminal content should be 100 to 150 meq / kg.

In addition, another aspect of the present invention is the bending phenomenon of the emitting polymer caused by the carbide of the volatile material accumulated on the spin nozzle surface when the polyamide is melt-spun at high speed for a long time using dicarboxylic acid as a chain regulator In order to improve the poor workability of radiation, such as single trimming, magnesium compound is added. Only by using the dicarboxylic acid and magnesium compound in this manner can improve the melt stability and spinning properties at the same time to produce a modified polyamide 6 fiber suitable for high-speed spinning.

The water used as the initiator in the present invention is preferably adjusted to 0.2 to 5% by weight in accordance with the properties of the polymerization apparatus.

The amount of the dicarboxylic acid used as the chain regulator in the present invention is 0.1 to 1.0% by weight, preferably 0.2 to 0.6% by weight. When the addition amount of the dicarboxylic acid exceeds 1.0% by weight, a problem that the degree of polymerization is remarkably lowered occurs. Therefore, in order to modify the polymer while maintaining the appropriate degree of polymerization, it is essential to add the compound within the above range.

Dicarboxylic acids usable in the present invention include alkanedicarboxylic acid, cycloalkane dicarboxylic acid, aromatic dicarboxylic acid, and examples of the alkanedicarboxylic acid include adipic acid, pivelic acid, suberic acid, Azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, and tridecanedioic acid, among which adipic acid and sebacic acid are preferable. Examples of cycloalkane dicarboxylic acids include cycloalkane-1,3-dicarboxylic acid and cyclohexane-1,4-dicarboxylic acid, with particular preference being given to cyclohexane-1,4-dicarboxylic acid And examples of the aromatic dicarboxylic acid include terephthalic acid and isophthalic acid.

In the present invention, a magnesium compound is added for the purpose of improving the reactivity, preventing bending and breakage caused by the flexibility of the yarn and melt spinning, and the amount of the magnesium compound is 10 to 100 ppm based on the magnesium element. . If the amount of the magnesium compound is less than 10 ppm on the basis of the magnesium element, the extension of the wiping period is insufficient, and if the amount of the magnesium compound is more than 100 ppm, the wiping extension period is good, but it is not preferable because it results in lowering of physical properties and poor chromaticity.

Examples of magnesium compounds usable in the present invention include magnesium oxide, magnesium acetate, magnesium chloride, magnesium stearate, and the like, and the magnesium compound is preferably used before or after polymerization.

In the production of the modified polyamide 6 fibers of the present invention, conventional additives and processing aids may be added in addition to the components described above. For example, heat stabilizers such as copper (I) iodide and copper (II) acetate, light stabilizers using manganese (II), matting agents such as titanium dioxide, antistatic agents such as polyalkylene oxides and derivatives thereof, and the like can be added. Can be.

The addition of the additive is possible at any stage of the production of the filament yarn of the present invention, the stabilizer is preferably added to the beginning of the polymerization to achieve stabilization at the start. And the moisture content of the manufactured chip is good to set it as 0.5 weight% or less. If the moisture content is high, depolymerization occurs during spinning and the sand in the final filament is poor, which causes a decrease in workability, so the moisture content is preferably controlled at 0.5% by weight or less.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by the following Examples.

Examples 1-3

100 parts by weight of caprolactam, 2 parts by weight of water as an initiator and dicarboxylic acid as a chain regulator are added as shown in Table 1 below, and a magnesium compound is added at 25 to 30 ppm as a polymerization agent for improving radioactivity. Was added to prepare a mixture. Subsequently, the mixture was placed in a polymerization reactor and polymerized at 265 ° C. for 4 hours. After removing the internal pressure and reacted for 2 hours at a reduced pressure of 480 torr to prepare a polyamide 6 chip so that each polyamide has a similar relative viscosity of about 2.55 level, the polymerization properties are shown in Table 1 below.

After extracting and drying the obtained polyamide 6 chip, the SUS-316 spinneret having 24 0.25 mmφ holes in a 40 mmφ extruder was used under a spinning temperature of 270 ° C. and a discharge rate of 38 g / min. Spinning, cooling with 20 ℃ cooling air at a wind speed of 0.6 m / min to impart an emulsion, and then winding at a speed of 5500 m / min to spin 70 d / 24f polyamide 6 filament, and The trimming occurrence time was measured and shown in Table 1 below.

Comparative Example 1

A polyamide 6 filament was prepared in the same manner as in Example 1, except that acetic acid was added as a chain regulator, and the physical properties and breakage time were measured and shown in Table 1 below.

Comparative Example 2-3

Except that the magnesium compound was not added to prepare a polyamide 6 filament in the same manner as in Example 1, the physical properties and the breakage time was measured and shown in Table 1 below.

Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Polymerization condition Chain conditioner TPA IPA TPA HAc TPA TPA Input content (% by weight) 0.21 0.21 0.45 0.15 0.21 0.45 Mg input content (ppm) 25 25 30 - - - Relative Viscosity (RV) 2.44 2.46 2.45 2.43 2.45 2.43 Extract content (%) 11.0 12.0 11.3 11.8 11.3 11.9 Physical properties after extraction and drying Relative Viscosity (RV) 2.52 2.57 2.51 2.59 2.53 2.52 Amine group content (A) 41 40 22 45 40 21 Carboxyl group content (C) 69 68 81 63 68 80 Total terminal content (A + C) 110 108 103 108 108 101 Properties after spinning Radio workability (%) 100 92 98 54 68 70 Strength (gr / De) 5.42 5.49 5.56 5.23 5.41 5.52 Elongation (%) 36 35 34 35 35 33 Single trimming occurrence time (hrs) 61 58 60 16 21 23 Canonical defects (/ 100 km) 0.26 0.79 0.16 1.76 1.26 1.50

Note) 1.TPA: terephthalic acid IPA: isophthalic acid HAc: acetic acid

2. The unit of terminal content (A or C) is meq / kg.

3. Relative Viscosity (RV) is measured at 25 ° C of 1g of polymer per 100ℓ of 95% sulfuric acid.

As confirmed through Table 1, when using dicarboxylic acid as a chain regulator, it is possible to obtain a filament of a higher strength than the existing, and when the magnesium compound is added during the polymerization, the frequency of single cutting occurs significantly lowered and workability It can be seen that this is greatly improved.

Example 4

As shown in Example 1, a polyamide 6 polymer prepared by using terephthalic acid as dicarboxylic acid and introducing magnesium compound in the initial stage of polymerization to improve the radioactivity, was used at 26 ° C at 4500 m / min and 6000 m, respectively. Spinning at / min, a relative viscosity (RV) of 2.61, a linear density of 60d / 24f to prepare a filament and measured the physical properties are shown in Table 2 below.

Comparative Example 4

For comparison with Example 4, the relative viscosity (RV) is 2.62, linear, spinning at 265 ° C. at 4500 m / min and 6000 m / min in the same manner as in Example 4, except that no magnesium compound was added. A filament having a density of 60 d / 24 f was prepared and the physical properties thereof were shown in Table 2 below.

Example 4 Comparative Example 4 Polymer condition Relative Viscosity (RV) 2.42 2.41 Chain regulator (% by weight) TPA (0.25) TPA (0.25) Mg content (ppm) 25 - TiO ₂ content (% by weight) 0.30 0.30 Residual Moisture Content (wt%) 0.046 0.044 Melt Spinning (265 ° C) Filament Viscosity (Rv) 2.51 2.51 Spinning speed (m / min) 5000 6000 5000 6000 Linear density (denier / fila) 70/24 7./24 70/24 70/24 Strength (gr / De) 5.3 5.5 5.2 5.4 Radio workability (%) 100 100 85 64 Single trimming occurrence time (hrs) 62 56 20 8 Canonical defects (/ 100 km) 0.26 0.28 1.14 1.26

As shown in Table 2, in the case of Comparative Example 4 shows the phenomenon that the frequency of single-break occurs significantly as the spinning speed increases, but when the magnesium compound is added in parallel as in the present invention, the frequency of short-break occurs significantly. You can see that.

According to the production method of the modified polyamide 6 fibers of the present invention, the melt stability and the radioactivity improvement effect are simultaneously obtained at the high speed spinning of the polyamide 6 fibers, and ultimately, the productivity improvement effects such as the high speed and the yield of the polyamide 6 fibers are improved. Can be obtained.

Claims (4)

In preparing high-speed spinning polyamide 6 fibers, 0.2 to 5% by weight of water as an initiator, caprolactam, 0.1 to 1.0% by weight of dicarboxylic acid, and 10 to 100 mg of magnesium compound based on magnesium element. Method for producing a modified polyamide 6 fiber, characterized in that it is prepared by the addition of ppm. The dicarboxylic acid according to claim 1, wherein the dicarboxylic acid is adipic acid, fibel acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, cycloalkane-1,3-dicar A process for producing modified polyamide 6 fibers, characterized in that it is selected from the group consisting of acid, cyclohexane-1,4-dicarboxylic acid, terephthalic acid, and isophthalic acid. The method of claim 1, wherein said magnesium compound is selected from the group consisting of magnesium oxide, magnesium acetate, magnesium chloride, and magnesium stearate. The method of claim 1, wherein the amine terminal content of the extracted chip is 30 to 60 meq / kg and the total terminal content is 100 to 150 meq / kg.